This invention is directed to an electronic timepiece battery monitoring circuit, and in particular to utilizing the voltage discharge characteristic of a battery to detect the impending failure thereof.
Heretofore, silver or mercury batteries have been the most commonly used power source in small sized electronic timepieces. Although silver and mercury batteries are capable of driving an electronic wristwatch at a predetermined voltage level over a considerable period of time, when the battery begins to fail, the voltage delivered thereby is dramatically reduced in a short amount of time. Accordingly, the rapid drop in voltage renders it extremely difficult to monitor the impending failure of such batteries and hence makes it difficult to replace the battery prior to the failure of same. Accordingly, a battery monitoring circuit wherein the period of time over which a power source deliverying voltage to timekeeping circuitry can be sufficiently increased to provide sufficient time to effect a replacement of the power source is desired.